When I open my camera everything disappears
That's actually very easy to explain.
The "0" you are pressing is the shortcut for Layer 10! That means you are NOT switching to camera view, but actually changing the layer from 1 (which contains all your geometry) to 10 (which contains nothing). That's why you see ... nothing.

To solve it. Check layer 1.



Make sure you press either what is the equivalent of NUMPAD 0 on your laptop or check "Emulate Numpad" in User Preferences.



Now your Number Row will act as your Numpad.

A final option without any hotkeys:



I hope this solves it for you.